The removal of sulfur-based species from liquid or gaseous hydrocarbon streams is a problem that has long challenged many industries. Hydrogen sulfide is a problem in the oil industry, particularly in the drilling, production, transportation, storage, and processing of crude oil, as well as waste water associated with crude oil. The same problems exist in the natural gas industry and geothermal power plants.
The presence of sulfur-containing compounds, such as hydrogen sulfide, can result in the deposition of sulfur containing salts, which can cause plugging and corrosion of transmission pipes, valves, regulators and other process equipment. Even flared natural gas needs to be treated to avoid acid rain generation due to SOx formation. Also, in the manufactured gas industry or coke making industry, coal-gas emissions containing unacceptable levels of hydrogen sulfide are commonly produced from destructive distillation of bituminous coal.
Since hydrogen sulfide has an offensive odor and natural gas containing it is called “sour” gas, treatments to lower hydrogen sulfide are termed “sweetening” processes. When a particular compound is used to remove or lower H2S, it is called scavenging agent or scavenger.